About six Afghan civilians were killed and 13 others wounded Sunday when a bus carrying civilians set off a roadside bomb in the country' s southern province of Helmand, a provincial government spokesman said Monday. "The mini-bus touched off an improvised explosive device (IED) in Nawmish district at around 3:00 p.m. local time. The blast killed six passengers and injured 13 commuters," spokesman Omar Zwak told Xinhua. Four passengers were not hurt in the incident, he said, blaming the Taliban insurgent group for targeting civilians. The Taliban insurgent group has largely been using home-made IEDs to launch suicide attacks and roadside bombings against Afghan troops and the NATO-led forces. The lethal weapons also inflicted casualties on civilians. More than 2,500 Afghan civilians were killed and over 5,000 wounded in Taliban-led attacks and violence last year, according to Afghan and UN assistance mission officials to Afghanistan. In a separated incident, six Taliban members were killed and four militants and two policemen were wounded in a gunfight which erupted in Jurm district in northern Badakhshan province on Sunday, the deputy provincial police chief Sayyed Jahanger Kiramat told Xinhua on Monday.